The invention relates to a coupling device.
Coupling devices are already known from DE 30 35 045 A1, EP 2 505 866 A2, DE 25 38 781 A1, with a friction-locking unit and a form-locking unit which is connected in parallel with the friction-locking unit and has two form-locking elements which can be connected to one another by form-locking, are disposed so as to be movable along a direction of actuation relative to one another and in each case have at least one claw. These publications also show claws of form-locking units which in each case have at least partially a top surface which is oriented obliquely with respect to the direction of actuation.
A coupling device for a motor vehicle is already known from the generic DE 10 2011 108 024 A1, with a friction-locking unit and a form-locking unit which is connected in parallel with the friction-locking unit and has two form-locking elements which can be connected to one another by form-locking, are disposed so as to be movable along a direction of actuation relative to one another and in each case have at least one claw. In this case two actuating units which are independent of one another and are provided for actuation of the friction-locking unit and the form-locking unit.
The object of the invention is in particular to increase the convenience of the coupling device.
The starting point for the invention is a coupling device for a motor vehicle with a friction-locking unit and a form-locking unit which is connected in parallel with the friction-locking unit and has two form-locking elements which can be connected to one another by form-locking, are disposed so as to be movable along a direction of actuation relative to one another and in each case have at least one claw.
It is proposed that the claws in each case have at least partially a top surface which is oriented obliquely with respect to the direction of actuation. As a result a particularly advantageously chamfered claw geometry can be provided, by which in a tooth-on-tooth position the form-locking elements can advantageously be guided by the top surfaces oriented obliquely with respect to the direction of actuation, so that the tooth-on-tooth position can be released in a controlled manner by an actuating force acting in the direction of actuation. In the tooth-on-tooth position a minimum overlap of the claws can already be achieved by the top surfaces oriented obliquely with respect to the direction of actuation, so that ratcheting can be prevented. Furthermore the tooth-on-tooth position can be continuously released by the top surfaces oriented obliquely with respect to the direction of actuation, so that a sudden release of the tooth-on-tooth position associated with a shock load can be prevented. Due to the obliquely oriented top surfaces of the claws, the actuating force by which one of the form-locking elements is engaged in the other form-locking element can be advantageously redirected and used for releasing the tooth-on-tooth position. Due to the redirected actuating force overpressure can be applied to the friction-locking unit, so that the form-locking elements can be rotated relative to one another by means of the actuating force. As a result the tooth-on-tooth position can be released reliably and comfortably, so that the convenience of the coupling device can be increased. A “coupling device” should be understood in particular to be both a clutch device and also a brake device. A “clutch device” should be understood in particular to be a device which is provided in order for two rotatably disposed coupling device elements to be selectively connected to one another non-rotatably or separated from one another. A “brake device” should be understood in particular to be a device which is provided in order for a rotatable coupling element and a stationary coupling, which is preferably connected non-rotatably to a stationary component or is formed integrally therewith, to be connected to one another non-rotatably or to be separated from one another as required. The stationary component is advantageously configured as a housing and particularly advantageously as a transmission housing. A “friction-locking unit” should be understood in particular to be a unit which produces the non-rotatable connection substantially by a frictional grip, such as for example a multiple-disc clutch or a multiple-disc brake. A “form-locking unit” should be understood in particular to be a unit which produces the non-rotatable connection substantially by form locking, such as for example a claw clutch or a claw brake. The friction-locking unit and the form-locking unit are preferably functionally disposed between the two coupling elements. The direction of actuation is advantageously parallel to an axis of rotation of the two form-locking elements. A “top surface” should in particular be understood to be a surface of a claw which faces the corresponding form-locking element. The top surface is preferably formed between two flanks of the claw. In the tooth-on-tooth position the top surfaces of the claws of the first form-locking element and the top surfaces of the claws of the second form-locking element preferably contact one another. The top surface has at least one surface normal with an axially directed directional component greater than zero. The expression “axial” relates in particular to the direction of actuation or the axis of rotation, so that the term “axial” designates a direction which extends in the direction of actuation or on the axis of rotation or parallel to the direction of actuation or the axis of rotation. “Obliquely with respect to the direction of actuation” should in particular be understood to mean that the top surface has at least one surface normal which is oriented obliquely with respect to the direction of actuation. “Provided” should be understood in particular to mean specially designed, equipped and/or disposed.
In order to save costs, it is further proposed that the top surfaces in each case are at least substantially planar, so that the top surfaces oriented obliquely with respect to the direction of actuation can be produced simply. A “planar top surface” should in particular be understood to mean a top surface which has no curvature. In this context “substantially planar” should in particular be understood to mean that at least 60%, advantageously at least 80% and particularly advantageously at least 90% of the top surface is planar.
Furthermore it is proposed that the top surfaces in each case have at least one surface normal with a directional component greater than zero directed in the circumferential direction. As a result the top surface can be directed in the circumferential direction, so that in the tooth-on-tooth position a circumferential force can be provided which can be used for releasing the tooth-on-tooth position and by which overpressure can be applied to the friction-locking unit for rotation of one of the form-locking elements. The expression “circumferential direction” relates in particular to the direction of actuation or the main axis of rotation, so that the term “circumferential direction” designates a direction which extends around the direction of actuation or around the axis of rotation. The circumferential direction preferably lies in a plane which is oriented perpendicular to the direction of actuation or to the axis of rotation.
In particular it is advantageous if the top surfaces in each case have at least one surface normal with a radially directed directional component equal to zero, so that the production of the top surfaces can be further simplified. The term “radially” relates in particular to the direction of actuation or the axis of rotation, so that the expression “radially” designates a direction which extends perpendicular to the direction of actuation or to the axis of rotation.
Furthermore, it is advantageous if the claws in each case have a coupling flank which in each case enclose an obtuse angle with a plane defined by the associated top surface. In this way the coupling flanks can be particularly large, so that the form-locking elements can be connected to one another particularly reliably by form-locking. A “coupling flank” should in particular be understood to be a flank of the claw which is provided for contacting a corresponding claw for torque transmission. The coupling flank is preferably formed by a surface of the claw, the surface normal of which advantageously points away from the claw. A “plane defined by the top surface” should in particular be understood to be a plane in which the top surface is disposed. In this context an “associated top surface” should in particular be understood to be a top surface which is formed by the claw which also forms the coupling flank with which the plane defined by the top surface encloses the obtuse angle.
Furthermore, it is advantageous if the claws in each case have opposite the coupling flank a flank which in each case encloses an acute angle with a plane defined by the associated top surface, so that the claws can particularly advantageously be chamfered on one side. The flank is preferably formed by a surface of the claw, the surface normals of which advantageously point away from the claw.
In an advantageous embodiment the coupling flanks each enclose a right angle with a plane which is disposed on the associated claw base and is oriented perpendicular to the direction of actuation, so that a high torque can be transmitted. A “plane defined by the top surface” should in particular be understood to be a plane in which an attachment surface is disposed by which the claw is fastened preferably on a main body. In this context an “associated claw base” should in particular be understood to be a claw base which is formed by the claw which also forms the coupling flank with which the plane disposed on the claw base encloses the right angle.
In a further embodiment according to the invention the top surfaces extend in each case as far as the claw base, so that impact forces upon release of the tooth-on-tooth position can be reduced or even prevented.
It is particularly advantageous if the claws are in each case disposed on the end face, so that a particularly advantageous coupling device can be provided.
Furthermore, it is proposed that the friction-locking unit has at least one friction-locking element which is permanently connected non-rotatably to one of the form-locking elements. As a result the form-locking element which is permanently connected non-rotatably to the friction-locking element can rotate relative to the engaging form-locking element due to the application of overpressure to the friction-locking unit, so that the tooth-on-tooth position can be released particularly simply. “Non-rotatably connected” should in particular be understood to be a connection in which a power flow averaged over a complete revolution is transmitted with an unchanged torque, an unchanged direction of rotation and/or an unchanged rotational speed.
Further advantages can be seen from the following description of the drawings. Three exemplary embodiments of the invention are shown in the drawings. The drawings, the description of the drawings and the claims contain numerous features in combination. Expediently, the person skilled in the art will also consider the features singly and combine them to form meaningful further combinations.